Unit 3 - Respiratory Lecture 2 Flashcards
What is pneumonia?
inflammation of the lung
What is pneumonia typically associated with?
an infectious process
What are the routes of pneumonia?
hematogenous or via airways
What are the two causes of hematogenous spread leading to pneumonia?
- diffuse blood-borne dissemination of fungi, bacteria, or viruses
- multifocal random bacterial seeding of the lung
What type of pneumonia does multifocal random bacterial seeding of the lung typically lead to and what lesion is associated with it?
embolic pneumonia - leading to multifocal abscesses
What type of pneumonia does diffuse blood-borne dissemination of fungi, bacteria, or viruses typically lead to?
diffuse interstitial pneumonia
What is the most common route of pneumonia via the airway?
airbone
What type of pneumonia does the airborne route typically lead to?
bronchopneumonia
What is the other cause of pneumonia via the airways?
inhalation of foreign material into the bronchial tree
What type of pneumonia is caused by inhalation of foreign material into the bronchial tree?
aspiration pneumonia
What clinical signs are typically associated with pneumonia?
cough, fatigue, fever, shortness of breath, and chest pain
What is intersitial pneumonia?
an inflammatory process that involbes the alveolar walls and the adjacent interstitium
What are some examples of diffuse interstitial pneumonia?
blood-borne dissemination of a virus, blood-borne dissemination of a toxin, blood-borne dissemination of a bacterin or blood-borne dissemination of a fungus
What gross features are associated with interstitial pneumonia?
heavy, rubber ‘meaty’ texture, the lung bounces back when indented, dark or mttled in color, will float, and may retain rib impressions
Is intersitial pneumonia typically diffuse or focal/multifocal?
diffuse
What are some key microscopic features of interstitial pneumonia?
alveolar and interlobular interstitium is expanded by exudate which causes interstitium to be thickened leading to its bouncyness
What are the three mechanisms of interstitial pneumonia?
- diffuse type I pneumocyte injury
- diffuse alveolar capillary injury
- systemic dissemination of infectious agents
What is the pathogenesis of diffuse type 1 pneumocyte injury?
- inhaled noxious agent- virus, toxic gas, ingested volatile chemicals
- diffuse injury to type I pneumocytes with necrosis and sloughing
- serfibrinous exudate accumulates in alvolar walls and on denuded alveolar surface
- if survives 48-72 hours hypertrophy and hyperplasia of type II pneumocyte to cover the denuded basement membraneii
What is the pathogenesis of acute interstitial pneumonia due to vascular injury?
- Septicemia, especially gram negative bacteria
- Diffuse injury to alveolar capillary endothelium by endotoxin
- Activation of pulmonary intravascular macrophages
- Increased vascular permeability which leads to fibrinosuppartive exudate accumulation in alveolar walls
What is the pathogenesis of chronic diffuse interstitial pneumonia?
- Agent disseminated via bloodstream to the alveolar wall or alveolar macrophages
- Macrophages release cytokines which recruit additional inflammatory cells into the alveolar wall and adjacent interstitium
- Lungs are diffusely dark, heavy, rubbery, and noncollapsing
What is embolic pneumonia preceded by?
bacterial infection and suppuration at another location
What is the pathogenesis of embolic pneumonia?
- bacteria or clusters of bacteria and fibrin enter the blood stream
- Lung acts as a filter for circulating particulates/bacteria
- Bacteria removed from bloodstream and form multifocal, random, pulmonary abscesses in all lung lobes
What are the common sources of bacteria or clusters of bacteria and fibrin that enter the bloodstream and cause embolic pneumonia?
liver abscesses, naval infection, contaminated catheters, vegetative valvular endocarditis
What gross lession (pattern) is seen in embolic pneumonia?
multifocal random nodular inflammatory foci in all lobes
What is the cause of aspiration pneumonia? (I know that I have asked this but repetition is key)
inhalation of foreign material into the bronchial tree
What foreign materials are often the cause of aspiration pneumonia?
non-sterile oral or gastric contents
What is the gross appearance of aspiration pneumonia?
anteroventral consolidation (looks like bronchopneumonia) and you may see ingesta in large airways
What common pattern of ingesta ‘flow’ into the lung is associated with aspiration pneumonia?
the fluid goes down the 1st drain that is encountered
In the bovine, what lung lobe is typically affected by aspiration pneumonia?
the right cranial lung lobe
In the canine, what lung lobe is typically affected by aspiration pneumonia?
the right middle lung lobe
What microscopic features are typically associated with aspiration pneumonia?
foreign material in the airways, necrotizing bronchiolitis, and bacterial bronchopneumonia
What is the mechanism of bronchopneumonia?
aerogenous entry of agents - particals 1-2 micrometers in diameter are deposited in the terminal bronchioles or alveoli and cause damage that leads to exudate accumulating in the alveoi and associated airways
What are the common causes of bronchopneumonia?
bacteria
What is the pathogenesis of bronchopneumonia?
- a massive exposure overwhelms the upper and lower respiratory tract mechanisms OR the upper and lower respiratory tract defenses are impaired by stress, poor environment or viral infection causing immunosupresion or decreased mucociliary clearance
- Bacteria reach the respiratory bronchiole and alveoli of the cranioventral lung
- Bacteria must be able to persist, replicate, and produce toxins to cause disease
- Damage to respiratory bronchiolar and alveolar epithelium; generates chemical mediators
- Incite acute inflammation; exudate accumulates in lumens of respiratory bronchioles and alveoli
- bronchopneumonia
What part of the lung is typically affected by bronchopnuemonia?
the anteroventral portion
What does a lung with bronchopneumonia feel like?
its fells solid (consolidated or hepatized)
What is the color of a lung with bronchopneumonia?
very dark, deep red
True or False- When you squeeze a lung with bronchopneumonia exudate will come out of the airways.
TRUE
What happens when you put a slice of a lung that has bronchopneumonia in formalin?
it sinks
What may be present in the trachea of an animal that had bronchopneumonia?
coughed up exudate
What is the pathological definition of consolidation?
the process of becoming solid, as changing of lung tissue from aerated and elastic to very firm
What microscopic changes can be seen with acute bronchopneumonia?
alveoli and adjacent airways are flooded with an exudate
What are some indications that a pneumonia is chronic?
organization of fibrinous exudate in airways, organization of fibrinous exudate in alveoli, organization of fibrinous exudate in interlobular septa, organization of fibrinous pleural exudate, sequestration of necrotic parenchyma and purulent exudate
What does organization of fibrinous exudate in airways lead to (indicate)?
bronchiolitis obliterans
What does organization of fibrinous exudate in alveoli lead to (indicate)?
alveolar fibrosis
What does organization of fibrinous exudate in interlobar septa lead to (indicate)?
septal fibrosis
What does organization of fibrinous pleural exudate lead to (indicate)?
pleural fibrosis +/- fibrous pleural adhesions
What does sequestration of necrotic parenchyma and purulent exudate lead to (indicate)?
abscesses
What are some characteristics of acute bronchopneumonia?
Hyperemia Serous to suppurative exudate/fibrin/hemorrhage Acute coagulative necrosis Same contour as normal It has been 0-72 hours
What are some characteristics of chronic bronchopneumonia?
Less hyperemia (tan to gray), fibrosis- pleural adhesions Thickened septa Abscesses Sequestered necrotic tissue Bronchiectasis Bronchiolitis obliterens Depressed lung Distorted contour Its been 7 days or more
What is the most economically significant disease of production animal species?
bacterial bronchopneumonia
What contributes to bacterial bronchopneumonias (general)?
multiple pathogens, management, and environmental factors
What environmental and management factors contribute to respiratory disease?
stress, exposure to new pathogens, environment, and lack of aquired immunity
What are some examples of stressors that can contribute to respiratory disease?
crowding, shipping, weaning, castration, dehorning, processing, mixing, vaccination, feed change, dehydration, new environment
What are some scenarios that can cause exposure to new pathogens thus contributing to respiratory disease?
mixing, comingling, no separation of air-space between age groups, and travel to shows
What are some environmental factors that can lead to respiratory disease?
temperature extremes, dust, ammonia, and pollution
Describe the different inflammation patterns between bronchopneumonia and interstitial pneumonia.
Bronchopneumonia - involving respiratory bronchioles and alveolar lumens
Interstitial Pneumonia - inflammation in alveolar walls and interlobular septs
Desctibe the differences in causative agents between bronchopneumonia and interstitial pneumonia.
Bronchopneumonia - typically bacterial
Interstitial pneumonia - viruses, toxins, gas, septicemia
Describe the differences in route of infection between bronchopneumonia and interstitial pneumonia.
Bronchopneumonia - air borne introduction
Interstitial pneumonia - hematogenous or airborne
Describe the difference gross appearances between bronchopneumonia and interstitial pneumonia.
Bronchopneumonia - cranioventral consolidation
Interstitial pneumonia - diffuse, heavy, rubbery, non-collapsing
How are pulmonary edema and interstitial pneumonia common in distribution?
they both tend to be diffuse
How are pulmonary edema and interstitial pneumonia common in gross weight?
they both will make the lung much heavier and swollen
Describe the differences between pulmonary edema and interstitial pneumonia in cut section.
Edema - clear fluid slowly leaks from cut surface
Interstitial pneumonia - no material leaks from lung
Describe the different appearance of the airways and trachea between pulmonary edema and interstitial pneumonia.
Edema - white froth in trachea and large airways Interstitial
Pneumonia - no material in trachea and large airways
How are bronchopneumonia and atelectasis common in distribution?
they both are often anteroventral
How are bronchopneumonia and atelectasis common in color?
they both may be dull red in color
Describe the difference in appearance of the surface of the lung between bronchopneumonia and atelectasis.
Atelectasis - surface is depressed compared to the adjacent lung
Acute Bronchopnuemonia - same contour as adjacent normal lung
Describe the difference in appearance of the airways and trachea between bronchopneumonia and atelectasis.
Atelectasis - no material within the trachea or expressed from the airways
Acute Bronchopneumonia - Creamy exudate coughed up into tracheal lumen and expressed from airways
Describe the difference in consistency between bronchopneumonia and atelectasis.
Atelectasis - soft and spongy
Acute Bronchopneumonia - firm (consolidated/hepatized)
Where do the majority of upper respiratory tract tumors arise?
in the nasal cavity
The majority of nasal tumors are ______ and may arise from any structure in the region.
malignant
What is the most common upper respiratory tract tumor in cats?
lymphoma
2/3 of the upper respiratory tract tumors in dogs are of what type?
epithelial - carcinomas
1/3 of the upper respiratory tract tumors in dogs are of what type?
mesenchymal - sarcomas
What clinical signs are associated with upper respiratory tract tumors?
epistaxis, mucopurulent discharge, facial deformity, epophoria (lots of tears), +/- neurologic signs
What are the common benign lung tumors of epithelial origin?
papillary adenoma or bronchioolar-alveolar adenoma
What are the common malignant lung tumors of epithelial origin?
adenocarcinoma, squamous cell carcinoma, bronchoiolar-alveolar carcinoma, etc.
What are the common benign lung tumors of mesenchymal origin?
hemangioma
What are the common malignant lung tumors of mesenchymal origin?
osteosarcoma/chondrosarcoma, hemangiosarcoma, histiocytic sarcoma, etc.
True or False - Primary lung tumors are common.
FALSE
The majority of lung tumors are malignant or benign?
malignant
What do lung tumors start as?
a solitary mass that metastasizes over time
What should you do if you observe multiple random tumor nodules in the lung?
search for a primary tumor somewhere else
What tumors of epithelial origin typically metastasize to the lungs?
mammary, thyroid, transitional cell carcinoma, prostate
What tumors of mesenchymal origin typically metastasize to the lungs?
osteosarcoma, hemangiosarcoma, malignant melanoma, lymphoma, vaccine-associated sarcoma
Where is the typical primary site for melanomas?
the nail bed or oral cavity
Where is the typical primary site for hemangiosarcomas?
right auricle, liver, spleen
What lesions can happen to the thoracic cavity?
pneumothorax, thoracic effusions, pleuritis, neoplasia
What are the types of thoracic effusions?
hydrothorax, hemothorax, chylothorax, pyothorax
What is a pneumothorax?
air in th pleural space
What can cause a pneumothorax?
air enters externally, air leaks from lungs, air enters the mediastinum
What clinical signs are associated with a pneumothorax?
respiratory distress
What gross lesions are associated with a pneumothorax?
atelectic lungs and a lack of negative pressure on the diaphragm
How do you diagnose a pleural effusion?
a chest tap
What is a sequela to pleural effusion?
atelectasis
What is pleuritis?
inflammation of the membrane surrounding the lungs and lining the chest cavity
What is the initial reaction of pleuritis typically (exudate form)?
fibrinous, purulent, or fibrinopurulent
What typically causes pleuritis?
Infectious - hematogenous, puncture wound/migrating foreign body, extenstion from lung infection, extension from thoracic lymphadenitis, migration down fascial planes of the neck, intra-thoracic esophageal perforation
What are some sequela to pleuritis?
accumulation of fluid exudate causing atelectasis, organization of fibrin leading to fibrous adhesions, mediastinal hyperplasia
What is a common thoracic cavity neoplasia?
mesothelioma
What is mesothelioma typically accompanied by?
thoracic effusion causing respiratory distress
